Main menu

Colt’s 1969 Piston Rifle

In 1969 Colt offered their model 703 as an upgrade to the M16 and M16A1 rifles. There is a well-traveled rumor that this rifle was known as the M16A2 because Colt was confident it would be adopted. While this could very-well be true, it is further confused by the fact Colt re-used the 703 designation for direct gas impingement M16A2 export models.

The Prototype 1 had a four position selector that was omitted on later models. Also omitted was the slot in the stock for a sling.

The following stats are taken from a May 1969 Colt data sheet.

Model

703 Prototype 1

M16A1

Caliber

.223

Overall Length

38.6″

Barrel Length

20″

Barrel Rifling

six groove, 1/12″ twist

Width

2.4″

Height (without magazine)

8.8″

Height (with 30rnd magazine)

10.2″

Weight (without magazine)

6.9 lbs

6.5 lbs

Weight (with loaded 30rnd magazine)

8.7 lbs

8.3 lbs

Weight of Reciprocating Group

1.33 lbs

1.0 lbs

Muzzle Velocity

3250 ft/sec

Muzzle Energy

1285 ft-lbs

Rate of Fire

gas adjustable 600-800 rpm

700-940 rpm

Operation

“Piston Impingement”

“Piped Gas”

Parts Count

143

164

Total Unique Parts

117

The firearm can be seen at Knights Firearm Museum. Interesting to note is the Knight’s museum appears to have Prototype 1, as well as a later 703 model; The World’s Assault Rifles claims only two were ever made. The M703 or CAR Model 703 should not be confused with the Colt ACR, a future prototype, which Olin developed the ammunition for.

The 703 piston and bolt carrier were attached via a “hinge”. The piston, piston hinge pin, and piston mounting block of the bolt carrier can be seen in the photo below.